Excavating machine



March 20, 1934. G. B. HEFFELFINGER EXGAVATING MACHINE Filed July 23, 1932 5 Sheets-Sheet l #VVE/V709. 67.5. HEFFELF/NGE?.

March 20, 1934- G. B. HEFFELFINGER 1,951,410

EXCAVATING MACHINE FiledJuly 23, 1932 Z, Sheets-Sheet 2 March 20, 1934 G. B. HEFFELFINGER 1,951,410

EXCAVAT ING MACHINE Filed July 25, 1932 3 Sheets-Sheet 3 /J/Is ATTORNEY Patented Mar. 20, 1934 Unirse STATES PATENT OFFICE EXCAVATING MACHINE Application July 23, 1932,` Serial No. 624,249

13 Claims.

This invention relates to an excavating machine and more particularly to means for counterbalancing the weight of the excavating element. It has been proposed heretofore to counterbalance the weight of the excavating element so that little power will be required to elevate the empty excavating element and practically the full power of the hoisting motor may be utilized to pull the excavating element through the bank and to lift the load contained therein, but no satisfactory means has been provided for compensating for the difference between the distance traveled by the excavating element and the distance which is feasible to permit the counterbalancing weight to travel. In the ordinary excavating machine the excavating element is movable from a position adjacent to or below the surface on which the machine rests to a position adjacent to the point of the boom, which is considerably above the superstructure of the machine. The counterweight is connected with the hoisting drum on the platform of the machine and if a single line connection is employed the weight must travel a distance equal to the distance traveled by the excavating element and this would require that the counterweight should be elevated a distance far above the platform, which obviously is undesirable and impracticable. If a multiline connection is employed the counterweight may move 3G a distance less than the distance traveled by the excavating element but the weight must be correspondingly increased.

One object of the present invention is to provide a counterbalancing mechanism of such a character that it will be required to travel a portion only of the distance traveled by the excavating element.

A further object of the invention is to provide such a counterweight mechanism comprising a o drum on which the counterweight cable is wound and means connected with the drum to cause the mechanism to travel a distance much less than the length of that portion of the counterweight cable which is wound onto or off the drum.

A further object of the invention is to provide such a counterweight mechanism with automatically controlled means to prevent the same from dropping in the event the counterweight cable breaks or is suddenly slacked off.

Other objects of the invention will appear as the mechanism is described in detail.

In the accompanying drawings Fig. 1 is a side elevation of a conventional excavating machine embodying my invention; Fig. 2 is a transverse sectional view taken on the line 2-2 of Fig. l and partially broken away; Fig. 3 is a side elevation of the counterweight mechanism; Fig. 4 is a rear elevation of the counterweight mechanism, partly in section and partly broken away; and Fig. 5 is a detail view of the locking mechanism.

In these drawings I have illustrated one embodiment of my invention and have shown the same as applied to a power operated shovel of a well known type. It will be understood, however, that this particular embodiment has been chosen g5 for the purposes of illustration only and that the counterweight mechanism may take various forms and may be applied to excavating machines of various kinds without departing from the spirit of the invention.

The power shovel here illustrated is of a conventional'design and comprises a platform 6 rotatably mounted on a base 'l which is carried by traction devices 8. A boom 9 extends upwardly and forwardly from the front end of the platform 6 and a dipper arm 10 is pivotally and slidably mounted on the boom between its ends, and has'at its outer end an excavating element'or dipper 11. A hoisting cable 12 is connected with the dipper and extends about a sheave 13 at a. the point of the boom and under a guide sheave 14 near the heel of the boom to a hoisting drum 15 on the platform 6. This hoisting drum may. be rotated by any suitable mechanism, not shown, such as the usual hoisting motor. An upright frame'is mounted on the rear portion of the platform 6 and constitutes a guide 'along which the counter-weight is moved. Preferably this frame comprises two upright frame members 16 rigidly connected one to the other and braced against lateral displacement, as by laterally extending members or wings 17. The connections between the two frame members are at Ythe forward edges of those members and the space between the frame members is unobstructed and adapted to receive the counterbalancing mechanism. It will be noted that in Figs. 2 land 4 the right hand frame member 16 and adjacent portions of the mechanism are omitted, butthese omitted portions are identical with the corresponding portions at the left hand side, as sho in those gures. Y Y f The counterbalancing mechanism comprises'a weight which may be of any suitable character but is here shown as a receptacle, Vor box-like 105 structure, 18, adapted to receive heavy material, j such as pig iron, Vscrap iron or the like, in such quantity as Vwill imp art thereto the desired weight. Rotatably mounted on the weight box is audrumrr 19 which is here shown as rigidly secured to a. V110 extend outwardly beyond the respective side walls of the weight box and each has secured to its outer end a pinion 26 which meshes with a rack 27. The racks 27 are rigidly secured to the rear edges of the respective frame members 16, which in the present arrangement are located at opposite sides of the weight box. A cable 28 has one end portion secured to and wound on the lcounterweight drum 19, extends upwardly and. about a sheave 29,'supported in an elevated po-` sition near the upper ends of the frame mem- 1oers 16, and has its other'end connected with the hoisting drum 15 in opposed relation to the hoisting cable 12,. As here shown, the counterweight Mcable 28 is wound on the same drum with the hoisting cable 12 but in the opposite direction. lt will be apparent, therefore, that .when the dip per is lowered and the hoisting cable unwound from the hoisting drum 15 the counterweight ca- "ble will be wound onto the hoisting drum and unwound from the counterweight drum 19 and that the'counterweight drum will cause thepinions 26 to rotate in such'a direction that they will travel upwardly along the racks 27 and kthereby elevate the counterweight mechanism as a whole. Due to the relatively large diameter of the counterweight drum 19 and to the reducing gearing which is interposed between the drum and the pinions 26 the distance traveled by the counterweight mechanism will equal only a small part of the distance traveled by the dipper. Whenv the hoisting drum 15 is actuated to wind the hoisting cable 12 thereon and elevate the dipper the counterweightl cable will be unwound from` vthe hoisting drum and the counterweight mechanism permitted to move downwardly by grav# ity. During this downward movement the pinions 26 will be actuated by the racks 27 to rotate the drum 19 in a direction to wind the cable 28 thereon. v

y'Ihe pinions 26 may be retained in mesh with Y the racks in'any suitable manner but, in the present instance, the framemembers 16 are prov vided with tracks 30 which extend parallel with Ybut in opposed relation to the racks 27, and guide members connected with the weight box ,travel along these tracks and in such relation thereto as to prevent the pinions moving rearwardly out of mesh with the racks. Preferably a yoke 31 is pivotally mounted on each shaft 23 and extends forwardly beyond the tracks 3o. This forwardly extending portion of the yoke has mounted thereon rollers 32 whichV engage the track 30 above and below the pinion 26. It is desirable that the rweight box shall be provided near its lower end with other rollers 33 to engage the tracks 30 and prevent the lower part of the weight boxirom swinging away from the supporting structure should the frame be inclined rearwardly, as when the machine is supported on an. inclined surface.

The upright frame is also provided at its,forward` portion Withother tracks, one of which is shown at 34 in Fig. 2, these tracks being arranged near the sides of the weight box and being engaged by rollers 35 secured to the upper and lower portions of the weight box and here shown as having shafts 36 journaled in bearings 37. These tracks and rollers serve to limit the forward movement of the weight box and to prevent the forward thrust from being imposed upon the racks and pinions. The rollers 35 may be provided with flanges 38 and thus also serve to hold the weight box against lateral movement. Preferably the pinions 26 are so mounted on the weight box that the center of gravity of the latter will be slightly oset from the center in a direction which will cause the weight box to tend to move Vforwardly by gravity, thus holding the rollers 35 in firm contact with their tracks and preventing any tendency of the weight box to move rearwardly or to sway when the machine is in its normal position.

Automatically controlled mechanism is provided to prevent the counterbalancing mechanism from dropping'in the event the counterweight cable should break or be suddenly slacked off.' ,This is preferably accomplished by locking the counterweight drum against rotation and thereby holding the pinions against rotation. For this purpose a ratchet wheel is connected with the drum for rotation therewith and a locking pawl cooperates with the ratchet wheel to lock the drum and pinions 26 against rotation in a direction to lower the mechanism. In the construction illustrated an annular member 382L is rigidly secured to the drum and has inwardly extending ratchet teeth 39, there being preferably one of these internal ratchet wheels at each end of the drum. Adjacent to each ratchet wheel a pawl 40 is mounted for movement into and out ofY engagement with the ratchet wheel. As lhere shown, this pawl is rigidly secured to a shaft 41 lournaled in bearings 42 at the top of the weight box 18. Rigidly connected with the shaft 41 is an arm 43 to the outer end of which is pivotally connected a rod 44 which extends through a guide bracket 45 and is acted 1 upon by a spring 46 confined between the bracket and asuitable stop on the rod, such as a nut 47. Connected with the arm 43 is a second arm 48 which extends upwardly along the counterwelght cable 28 and has mounted thereon a grooved roller The roller 49V is Y modate itself to the changing position of the cable as the latter is wound onto the drum. The arm 48 is so arranged with relation to the pawl .40 that when the roller 49 is in contact with the cable and the cable is taut the pawl will be held in its retracted or inoperative position, and the spring 46 compressed. Should the cable break or become slack the spring 46 will be released and will expand and move the pawl 40 into its operative mounted on the shaft 41 and connected with they arm 43 Yby a rod or turn buckle 51 the ends ofY which are threaded into nuts 52 rotatably mount- Aed in therrespective arms.

While I have shown and described one embodiment of my invention I wish it to be understood that I do notjdesire to be limited to the details thereof as variousmcdifications may occur to a 'person skilled in the art.

A 1. 'A counterbalancingv mechanism?.for i the :Texcavating `element of excavating'machinefcomprising'` an uprightfframeimountd "onf saidlmachine-and having rearwardly-extending side'members provided at theinrear 'dgeswithtoothed racks, oppositely facingvtracks; arranged ini front of andA parallel with said racksfa` counterweight mounted between .said =side members andi-extending rearwardly beyond the-same, pinlons-carrid by saidcounterweight -ariden'gagingv saidi'racks, a druml rotatably mounted 4on said counterweight and operatively "connected with saidpinions, a sheave mounted on the upper -portionrof 'said frame, a ycable lconnecfzted 'with y=sai`d excavating element, extending about said sheaveLandfWourid on said drum to support saidf'counterweightlland control rthe rotation of l said pinions, Pand parts carried by said counterweight andfengagingfsaid tracks to.r control the fore and aft rnovemer'itfof said counterweight.

2. A counterbalancirig mechanism'fortle excavating element of an excavating machine,` comprising an upright frame mountedfonnsaid nia:- chine and having rearwardly-extending 1sidemembers providedat'their rear edges with toothed racks, said frame also having vviorw'ardly"facing tracks arrangedv in front'offand parallel with said racks, a counterweight mounted'lfbetween'saidfside members and extending rearwardly Hbevond fthe same, pinionsYY carried by'y said; counterweight I and engaging sai'df racks, afdrum` rotatably mounted on said counterweight and operatively connected with' said pinions, asheave mounted 'on-the upper portion of said'fra'me, a cable connected-with'said excavating element, extending about said sheave and wound on saiddrum to -support said counterweight and control the `rotation of saidpinions, members pivot/ally 4mounted ron said counterweight adjacent to said'pinions, and'rollersfcarried by said pivoted members andengaging'fsaid tracks to retain' said pinions inengagement ywith sai'd racks.

3. A counterbalancing mechanism Afor the excavatingA element of an excavatingfma'chine; comprising an'upright l'frarnemounted on said machine and havingy rearwardly 'extendin'gside' members provided at their 'rear edges with toothed racks, oppositely| facing tracks'arran'ged lnfront' of and parallel with said racks, a Acounterweight mounted between said side membersandk extending rearwardly 'beyond the samefa drum rotatably mounted on said counterweight and operatively connected with said pinions,'asheave'mountedon the upper portion'of saidframe, a cableV connected with said Aexcavating element, -`extending about said sheave and Wound'on said drum'to support said counterweight, pinions vrotatably mounted on said counterweight, engaging the respective racks and operatively connected with said drum, said pinions being so arranged With relation to the center of gravity of said ycounterweight that the force of gravity will tend normally to move said pinions toward said racks, and means carried by said counterweight and engaging said tracks to limit the swinging movement of said counterweight.

4. A counterbalancing mechanism for the excavating element of an excavating machine, comprising a vertically movable counterweight, a toothed rack supported on said machine adjacent to the path of said counterweight, a pinion rotatably mounted on said counterweight and engaging said rack, a drum rotatably mounted on said counterweight and operatively connected withsaid pinion, a sheave supported near the upper end of said* rack,fa cable connected witlrsaid excavating element, extending about said sheave and Wound on said drum to support said counterweight and controlx the rotation of said pinion, oppositely facingtracks extending parallel with said rack on that side thereof opposite said pinion, a part carried by said counterweight and engaging one of said tracks to limit the movement of said pinion to- Wardfsaid rack, and a second. part carried by said counterweight and engaging the other of said tracks2 to limit the movement of said pinion in a direction to disengage the same fro-m said rack.

5. 'A counterbalancing mechanism for the excavating element of an excavating machine, comprising a 'vertically .movable counterweight, a toothed rack-supported on said machine adjacent to the path of saidv counterweight, a pinion rotatably? mounted on said counterweight and engaging said 1 rack, a drum rotatably mounted on said counterweight and operatively connected with saidpinion, a sheave mounted adjacent to the upper end of said rack, a cable connected with said excavating element, extending about said Sheave and wound on said drum to support'said counterweight and control the rotation of said pinion, a-track arranged in opposed relation to said rack on that side thereof opposite said pinion, anda guide member pivotally mounted on said counterweight and having parts engaging said track above and below said pinion to hold .the latter-in engagement With'said rack.

v6. A counterbalancing mechanism for the excavating element of an excavatingr machine, comprising .a vertically movable counterweight, a toothed' rack supported on said machine adjacent to the'path of said counterweight, a pinion ro'- tatabl'y'mounted on said counterweight and engaging said rack, a drumfrotatably mounted on said counterweight and operatively connected withfsaidpinion, a sheave supported adjacent to the upper end of said rack,'a cable extending about said sheave and connected with said drum and said excavating element, a track arranged iii-opposed relation to said rack, a yoke pivotally mounted on said counterweight and rollers carried by said yoke and engaging said track.

'7. A counterbalancing mechanism for the 'excavating element of an excavating machine, comprising a vertically movable counterweight, a toothed rack supported on said machine adjacent to the path of said counterweigha'a pinion rotatably mounted on lsaid counterweight and engaging said rack, a drum rotatably mounted' on said counterweight and operatively connected with said pinion, a sheave supported near the rotatably mounted on said counterweight and engaging said rack, a drum rotatably mounted on said counterweight and operatively connected with said pinion, a sheave supported near the upper end of said rack, a cable connected with said excavating element, extending about said Vcavating element of an excavating machine, comsheave and Wound on said drum to supportv said counterweight, a device carried by said counter- Weight and movable into and out of a position to lock said pinion and said drum against rotation in a direction to lovver said counterweight, and means controlled by said cable to hold said device in an inoperative position when said cabie is taut. Y

9. A counterbalancing mechanism for the excavating element or" an excavating machine, comprising a vertically movable counterweight, atoothed rack supported on said machine adja-V cent to the path of said counterweight, a pinion rotatably mounted on said counter-weight and engaging said rack, a drum rotably mounted on said counterweight and operatively connected with saidv pinion, a sheave supported near the upperend of said rack, a cable connected With said excavating element, extending about said shea-Ve and Wound on said drum to: support said counterweight, a locking device movableinto and out of a position to heid said counteriveight against downward movement, a member conf nected with said locking device and normally'engaging said cable to hold said locking Ydevice in its inoperative position when said cable is taut, and means acting on said locking device to move the same to its operative position when said cable is slack.

1). A counterbalancing mechanism `for the exprising a vertically movable counterweight, a toothed rack supported on said machine adjacent to the path of said coimterweight, a pinion ifo-ftatably mounted on said counterweight and engaging said rack, a drum rotatably moinitedron said counterweight and operatively connected With said pinion, a sheave supported near the upper end of said rack, a cable connected With said excavating element, extending about saidsheave and wound on said drum to supportsaid countervveight, a device carried by said counter- Weight and movable into locking relation to. said drum to hold the same against rotation in a direction to: lower said counteriveight, yieldable means tending to move said device to its operative position, and a part connected with said device and arranged to engage said cable and hold said device in an inoperative position When saidV 11. A ccunterbalancing mechanismor the vexcavating element of an excavating machine, comprising a vertically movable counterweight, a toothedY rack supported on said machine adjacent to the path of said counterweight, a pinion rotatably mounted on said counterweight and engaging said rack, av drum rotatably mounted on said counterweig'htand operatively connected with said pinion, a sheave supported near the upper end ,of said rack,fa cable connected -With said excavating element, -extendingabout said sheave and Wound Von said drum to support said counter` Weight, atoothed member connectedWithA said drum forgrotation therewith, a -pawl carried byy engaging said rack, a drum rotatably mounted on said counterweight and operatively connected withl said pinion, a sheave supported near the upper end of said rack, acable extending about saidfsheave and connected with said drum and said excavating element, a toothed member connected with said drum4 for rotationv therewith, a

pawl, an arrnrigidly connected Withsaid pawl, a spring acting on said arm to move said pawl into engagement With said toothed member, a second arm pivotallymounted on the axis of said pavvl,

adjustable means forconnecting said arms one with theother, and a roller carried by said second -armto engage said cable and hold said paWl against movement by said spring when said cable is taut.

13. A counterbalancing mechanism for the exy Y cavating element or" an excavating machine, com prisinga vertically movable counterweight, a toothed rack supported on said machine adjacentto the path of saidfcounterweight, a pinion vrotatablymounted on said countervveight, and

engaging said rack, a drum rotatably mounted on said counterweight and operatively connected withl said pinion, a sli-cave supported near the upper end of said rack, la cable connected with said excavating element-,5 extending about said sheave and woundon said drum to support said counteivveighha toothed member, a locking member to engage said toothed member and prevent downward movement orsaid countervveight, 'means tending to move said locking memberinto engagementvvith said toothed member, and apart v` connectedfvvith `said locking member and arranged to engage said cable and hold said lockingmember out oi engagement with said toothed member when-,said cable is taut.

GLEN B. HEFFELFINGER I' iso 

